Waterproof watch



May 24, 1966 G. G. ENSIGN 3,252,280

WATERPROOF WATCH Filed March 9, 1964 [1: v5.22 zur' George G. Ens/g United States Patent 3,252,280 WATERPROOF WATCH George G. Ensign, Elgin, Ill., assignor to Elgin National Watch Company Filed Mar. 9, 1964, Ser. No. 350,375 6 Claims. (Cl. 58-90) This invention relates to a waterproof watch and,

more particularly to a simple, inexpensive and readily installed sealing structure which prevents entry of water or dust into a watch case around the stern which couples the crown to the setting mechanism.

According to this invention, an annular bushing of resilient material surrounds the watch stem and is compressed between a surface portion of the watch movement and an internal surface portion of the watch case which surrounds an opening through which the stern extends. The bushing is so compressed as to provide a tight sealing engagement with such surface portions and also with the stem, to provide a water and dust-tight seal, while not interfering with the movement of the watch stem, and while not exerting undue pressure on the watch movement.

According to an important feature of the invention, the bushing when in an unstressed condition before assembly has internal cylindrical and beveled or frustoconical surface portions on a common axis meeting at a cylindrical edge approximately midway between opposite ends of the bushing. Preferably, the frustoconical surface portion faces inwardly when the bushing is assembled, to engage the watch movement. With this arrangement, the deformation of the bushing is such as to insure the attainment of a proper seal without interfering with the setting operation of the stem, or the operation of the watch movement.

According to a specific feature, the chamfer angle of the frusto-conical surf-ace relative to a plane transverse to the axis is on the order of 45 or less.

Additional important features relate to the provision of a bushing having preferred characteristics and a composition such as to insure the attainment of a proper seal while not interfering with the setting operation or the operation of the watch movement. Preferably, the bushing is of plastisol material having a certain composition to provide the optimum sealing resiliency and durability characteristics. It has been found also that the material should preferably have a scleroscope reading of from 32 to 39, and most preferably from 35 to 37, to obtain the proper sealing action, regardless of the composition of the material. It has been found further that the best results are obtained when the bushing is compressed to from 60 to 90% of its unstressed or free height or thickness, and most preferably when'it is compressed to 75% of its free height or thickness. i

This invention contemplates other objects, features and advantages which will become more fully apparent from the following detailed description taken in conjunction with the accompanying drawings which illustrate preferred embodiments in which- FIGURE 1 is a sectional View showing a sealing bushing between portions of a case and a movement of of a watch, according to the principles of this invention;

FIGURE 2 is a sectional view similar to FIGURE 1, but showing a modified construction;

FIGURE 3 is a top plan view of the bushing prior to assembly in the watch;

FIGURE 4 is a side elevational view of the bushing prior to assembly in the watch; and

FIGURE 5 is a view showing how the bushing in its unstressed condition fits freely on the watch stem.

3,252,280 Patented May 24, 1966 Reference numeral 10 generally designates a watch constructed according to the principles of this invention, and comprising an annular bushing 11 of resilient material disposed in surrounding relation to a stem 12 which is integrally secured to a crown 13 and which is connected to a setting mechanism within the watch movement 14, only a frame portion of the movement 14 being illustrated.

The bushing 11 is compressed between a surface portion 15 of movement 14 and a surface portion 16 of a case 17, to sealingly engage such surface portions 15 and 16; and to also sealingly engage the stem 12 to provide a water and dust-tight seal.

In the embodiment of FIGURE 1, the case 17 has an integral inwardly extending annular rib or ring 18 surrounding the bushing 11. In the embodiment of FIG- URE 2, the rib or ring 18 is not used, but the construction is otherwise the same as in FIGURE 1.

In both embodiments the ring 11 is so deformed by the compressive forces applied thereto, that only an internal surface portion 19 of limited area engages the stem 12, but with increased unit pressure, to provide maximum sealing action, while minimizing the restriction on movement of the stem 12. It will be noted that the internal surface of the bushing 11 is smooth1y curved away from the portion 19 as illustrated. I

The top plan and side elevational views of FIGURES 3 and 4 show how the bushing 11 is shaped in its unstressed condition prior to assembly, in order toobtain the configuration as illustrated in FIGURES 1 and 2, when compressed between the watch movement 14 and the case 17. In particular, the bushing 11 in its unstressed condition has an internal cylindrical surface portion 21 and an internal frust-conical surface portion 22 which meets at a cylindrical edge 23 which is approximately midway between one end surface 24 of the bushing 11 and an opposite end surf-ace 25 thereof.

As shown in FIGURE 4, the chamfer angle of the surface 22 is approximately 45 with respect to a line transverse to the axis of the surface. Preferably, the angle should not exceed 45 and it may be reduced to an angle on the order of 30 at which the frusto-conical surface portion extends all the way to meet an outer cylindrical surface portion 27 of the bushing. As shown, the height or thickness of the bushing, i.e. the distance between end surfaces 24 and 25, is preferably about equal to the diameter of the internal cylindrical surface 21, and about one-third the diameter of the outer surface 27. The diameter of the internal cylindrical surface portion 21 should be about equal to the diameter of the stem 12, and preferably slightly larger, to provide a free fit on the stem 12 before assembly, as illustrated in FIGURE 5.

The material of the bushing 11 is preferably a plastisol material comprising by weight 35 to 55% high molecular weight polyvinyl resin, 45 to 65% octyl phthalate and 0.1 to 0.5% barium-cadmium organic liquid stalbilizer, and most preferably approximately 45% high molecular weight, polyvinyl resin, 55% octyl phthalate and 0.2% barium-cadmium organic liquid stabilizer. The resin may preferably be of the type made by Firestone Plastics Co. under the trademark Exon No. 654, while the stabilizer may preferably be of a type made by Argus Chemical Corp., under the trademark Mark M. With such composition, it is possible to obtain the optimum resiliency and durability characteristics.

It is possible to use other materials but it is found that in any case, the material should be such as to provide a scleroscope reading in the range of from 32 to 39, and preferably in a range of from 35 to 37.

The bushing should preferably be compressed so that its height or thickness is reduced to from to 60% of its height or thickness in the unstressed condition, and

most preferably to about 75% of its height or thickness in the unstressed condition.

The use of materials with characteristics as set forth above is particularly desirable in watches such as certain However, the bushing can be used in other types of.

watches, such as those having conventional side set cases.

.It will be understood that modifications and variations may be effected without departing from the spirit and scope of the novel concepts of this invention.

I claim as my invention:

1. In a watch including a case having an opening therein, a crown, a stem extending from said crown, a watch movement for operation from said stem disposed within said case and including a surface portion in spaced relation to an internal surface portion of said case about said opening therein, the improvement comprising an annular bushing of resilient material surrounding said stem and compressed "between said surface portions into sealing engagement therewith and with said stem to provide a water and dust-tight seal, said annular bushing in an unstressed condition before assembly being symmetrical and having internal cylindrical and frusto-conical surface portions on a common axis meeting at a cylindrical edge approximately midway between opposite ends of said bushing, the chamfer angle of said frustro-conical surface relative to a plane transverse to said common axis being on the order of 45 or less and said resilient material having a resiliency such as to produce a scleroscope reading in the range of from 35 to 37.

r 2. In a watch including a case havingan opening therein, a crown, a stem extending from said crown, a

watch movement for operation from said stem disposed within said case and including a surface portion in spaced relation to an internal surface portion of said case about said opening therein, the improvement comprising an annular bushing of resilientmaterial surrounding said stem and compressed between said surface portions into sealing engagement therewith and with said stem to provide a water and dust-tight seal, said annular bushing in an unstressed condition before assembly having internal cylindrical and frusto-conical surface portions on a common axis meeting at a cylindrical edge approximately midway between opposite ends of said bushing, said frusto-conical surface portions being in facing relation to said surface portion of said movement in the assembled condition of said bushing. v

3. A watch as in claim 2 wherein said annular bushing is made from a plastisol material having a resiliency such as to produce a scleroscope reading in a range from 32 to 39.

4. A watch as in claim 2 wherein said annular bushing is made from a plastisol material comprising by weight 35 to 55% high molecular weight polyvinyl resin, to 65% octyl phthalate and 0.1 to 0.5% barium-cadmium organic liquid stabilizer.

5. A watch as in claim 2 wherein said annular bushing is made from a plastisol material comprising by weight approximately 45% high molecular weight polyvinyl resin, octyl phthalate and 0.25% barium-cadmium organic liquid stabilizer.

6. A watch as in claim.2 wherein said bushing is compressed when assembled so that the distance between the ends of said bushing is from to of the distance between said ends when the bushing is in an unstressed condition before assembly.

References Cited by the Examiner UNITED STATES PATENTS 2,701,969 2/1955 Meredith 73 131 2,773,347 12/1956 Froidevaux 5s 9o 2,913,869 11/1959 Schlenker 58-90 FOREIGN PATENTS 216,197 11/1941 Switzerland.

267,735 7/1950 Switzerland.

LEO SMILOW, Primary Examiner. LEYLAND M. MARTIN, Examiner.

GERALD F. BAKER, Assistant Examiner. 

1. IN A WATCH INCLUDING A CASE HAVING AN OPENING THEREIN, A CROWN, A STEM EXTENDING FROM SAID CROWN, A WATCH MOVEMENT FOR OPERATION FROM SAID STEM DISPOSED WITHIN SAID CASE AND INCLUDING A SURFACE PORTION IN SPACED RELATION TO AN INTERNAL SURFACE PORTION OF SAID CASE ABOUT SAID OPENING THEREIN, THE IMPROVEMENT COMPRISING AN ANNULAR BUSHING OF RESILIENT MATERIAL SURROUNDING SAID STEM AND COMPRESSED BETWEEN SAID SURFACE PORTIONS INTO SEALING ENGAGEMENT THEREWITH AND WITH SAID STEM TO PROVIDE A WATER AND DUST-TIGHT SEAL, SAID ANNULAR BUSHING IN AN UNSTRESSED CONDITION BEFORE ASSMEBLY BEING SYMMETRICAL AND HAVING INTERNAL CYLINDRICAL AND FRUSTO-CONICAL SURFACE PORTIONS ON A COMMON AXIS MEETING AT A CYLINDRICAL EDGE APPROXIMATELY MIDWAY BETWEEN OPPOSITE ENDS OF SAID BUSHING, THE CHAMFER ANGLE OF SAID FRUSTRO-CONICAL SURFACE RELATIVE TO A PLANE TRANSVERSE TO SAID COMMON AXIS BEING ON THE ORDER OF 45$ OR LESS AND SAID RESILIENT MATERIAL HAVING A RESILIENCY SUCH AS TO PRODUCE A SCLEROSCOPE READING IN THE RANGE OF FFROM 35 TO
 37. 